JPS617902A - Load driving control device - Google Patents

Abstract

PURPOSE:To obstruct a start of operation of a load as soon as a power source is turned on, by constituting a titled device so that on- and off-states of an output bit signal from a controller are monitored directly, and the power source is supplied to the load only when they are all off. CONSTITUTION:A series circuit of a parallel circuit of diodes 52 and an electromagnetic contactor 51 is connected in series to a parallel circuit of transistors 21-22, therefore, when at least one of output bits of a controller 2 is on, the electromagnetic contactor 51 is operated. Also, a contact 511 is opened, therefore, even if a power source turning-on switch SW is closed, no operating path is formed, and accordingly, no power source is supplied. On the other hand, when the output bits of the controller 2 are all off, the electromagnetic contactor 51 is not operated, and when the switch SW is closed, an electromagnetic contactor 11 is operated, and the power source is supplied to a driving device 3 through its contacts 111, 112. Thereafter, driving elements 31-3n are opened or closed in accordance with on- and off-states of the output bit from the controller 2, therefore, a load is driven.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field to which the Invention Pertains] This invention relates to the control of a plurality of loads (
The present invention relates to a load drive control device that drives (controlled equipment), particularly a load drive control device that has accident prevention and load protection functions.

[Prior art and its problems]

FIG. 2 is a configuration diagram showing a conventional example of such a load drive control device. In the figure, 1 is a power supply circuit, 2 is a controller such as a PC, 3 is an expansion device, 4 (41 to 4n) is a load, SW is a power supply switch, P and N are power supply buses, CP, CN is a control power supply bus. The power supply circuit 1 includes an electromagnetic contactor (relay) 11 and its contacts 111 and 112, the controller 2 includes output transistors 21 to 2n, and the drive device 3 includes a TRIAC (trade name) or similar device. Load drive elements 31 to 3n are provided, respectively.

When the power-on switch SW is turned on at this point in time, the electromagnetic contactor 11 operates and the contacts 111 and 112 are closed, thereby supplying power to the drive device 3. Therefore, for example, when the corresponding transistor 21 is turned on to drive an arbitrary load 41, the load driving element 3 connected to the control power lines CP and CN
1 is driven, the load 4 is driven through this driving element 31.
1 operates upon receiving power supply. Such operations are performed without any particular problem as long as the controller 2 is operating normally, but due to a runaway program in the controller 2 expansion or a malfunction in the output section (not shown), etc., the controller 2 malfunctions and outputs ON information. Sometimes I leave it alone. If, in such a case, the power supply switch SW is turned on, the electromagnetic contactor 11 is turned on and driving power is supplied to the drive device 3, and in this state, any one of the load drive elements 31 to 3n ( 31) is open, the load 4i suddenly starts moving, which is likely to cause a dangerous situation (unexpected accident, etc.) and has a large effect on the load. For this reason, it is necessary to monitor the output state of the controller 2, which has conventionally been done in the following manner for nematodes.

That is, each output bit signal (on,
One example is a method in which an auxiliary relay is provided to receive each of the output pit signals (off signal), and the contacts of the two are connected in parallel for monitoring, and another is a method in which one representative point of the output pit signal is monitored.However,
The former has the disadvantage of high cost because it requires a number of auxiliary relays according to the number of output bits, and the latter has the disadvantage of insufficient checking and lack of reliability because it does not check all output pits. There is.

[Purpose of the invention]

The present invention was made under these circumstances, and it is an object of the present invention to provide a load drive control device that is capable of reliable and safe driving with a simple and inexpensive configuration.

[Key points of the invention]

This invention directly monitors the on/off states of the output bit signals from the controller and supplies power to the load only when all of these are off, thereby allowing the load to operate at the same time as the power is turned on. This is designed to prevent unexpected accidents and protect the load.

[Implementation of the invention]

FIG. 1 is a block diagram showing an embodiment of the present invention.

As is clear from the figure, this embodiment uses an electromagnetic contactor (
It is characterized by the provision of an output pit monitoring circuit 5 consisting of a relay) 51, its contacts 511, a diode 52, and the like. Note that 113 is a self-holding contact of the electromagnetic contactor (relay) 11. The parallel circuit of the diode 52 and the series circuit of the electromagnetic contactor 51 are connected in series to the parallel circuit of the transistors 21 to 2n. Control power source @c p.

Since it is connected between CN and transistors 21 to 2n
If at least one of the output bits of the controller 2 is on, the electromagnetic contactor 51 operates and its contacts 511 are opened. Therefore, even if the power-on switch SW is closed, the electromagnetic contactor 11 No operating path is formed and therefore no power is supplied to the drive device 3. On the other hand, if all the output bits of the controller 2 are off, the electromagnetic contactor 51 does not operate, and its contact 511 is in the position shown, so the electromagnetic contactor 11 operates when the switch SWO is closed, and its contact 111゜11
Power is supplied to the drive device 3 via the drive device 2.

Therefore, after that, the driving elements 31 to 3n are opened or closed depending on the on/off state of the output bit from the contraler 2, and thereby the loads 41 to 4n are driven. At this time, since the electromagnetic contactor 51 is driven, the operating path of the electromagnetic contactor 11 via its contact 511 is cut off, but since it is self-held by its contact 113, no problem occurs. .

〔Effect of the invention〕

According to this invention, the on/off state of the output bit from the controller is directly monitored by a parallel circuit of diodes, which is simpler and cheaper than conventional methods.
Furthermore, the advantage is that a highly reliable load drive control device can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS [FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram showing a conventional example. Code explanation 1...Power supply circuit, 2...Conn)o
-Ra (PC), 3... Drive device, 4...
・Load (controlled device), 5...output bit monitoring circuit, 11, 51...magnetic contactor (relay),
l11# 113s 51t...Contact, 21~
22...Output transistor, 31-3o...
...Load drive purple, 52...Diode,
SW...Power on switch, P, N...
...Power supply bus, CP, CN... Control power supply bus.

Claims (1)

[Claims] In a load drive control device comprising a control means for selectively outputting on/off commands to a plurality of loads, and a drive means for supplying power to and driving the loads based on the commands, the controller A load drive device is provided with a power supply control means that directly monitors the outputs of the outputs and enables power supply to the load only when all of them are off, and that the means prevents the load from operating at the same time as the power supply starts. Control device.